8. The observation of the facts of the geological succession of the forms
of life.
1. Notwithstanding the elaborate disguise which fear of the powers that
were led Descartes to throw over his real opinions, it is impossible to
read the "Principes de la Philosophie" without acquiring the conviction
that this great philosopher held that the physical world and all things in
it, whether living or not living, have originated by a process of
evolution, due to the continuous operation of purely physical causes, out
of a primitive relatively formless matter. [Footnote: As Buffon has well
said:--"L'idée de ramener l'explication de tous les phénomènes à des
principes mecaniques est assurement grande et belle, ce pas est le plus
hardi qu'on peut faire en philosophie, et c'est Descartes qui l'a
fait."--_l. c._ p. 50.]